The examples that Thomas Shinder or any body else gives to configure dcomcnfg.exe do not touch upon configuring any port under "Default Protocols" under TCP/IP when dcomcnfg.exe is run. I have followed his examples exactly. I have added Everyone to "Custom Access permissions", "Custom Launch Permissions", "Custom Configure Permissions" and done all other configurations. However I have to do this this extra configuration for our mail to be received. I have to add port 25 as an internet port - not as intranet - for mail sent to our domain to be received. Why is there this further facility to configure TCP/IP? When I add Port 25 as an internet port, all other ports except Port 25 appear under Intranet ports!!!! Ports 1-24 and Ports 26-... appear as intranets ports . What does this mean? I have already run the Secure Mail Server Publishing Wizard and configured it to listen on Port 25. This extra bit of configuration under TCP/IP under Default Protocols is really confusing !!! More so because nowhere does any one touch upon it. Our SMTP server that receives our mail is internal. Any explanation will be greatly appreciated.